"Welcome Horizons" is, in fact, a rendition of the title theme for New Horizons. It can first be heard in-game playing from a tape deck outside of Resident Services during the bonfire party to celebrate the first night living on the island. It can be obtained from Tom Nook after K.K. visits for the first time. The song can also be heard in Animal Crossing: Pocket Camp, on the Portable Radio furniture item from the Island Excursion Invite Set.

The track features heavy usage of brass instruments, ukulele, and maracas, with bongos and accordions also present, along with a tambourine being shaken, giving off a tropical vibe.